Device for preventing humidity in enclosures containing insulating parts



Feb. 5, 1952 A. LATOUR 2,584,889v

DEVICE FOR PREVENTING HUMIDITY IN ENCLOSURES CONTAINING INSULATING PARTS Filed July 23. 1947 3 Sheets-Sheet l Feb. 5, 1952 LATOUR 2,584,889

DEVICE FOR PREVENTING HUMIDITY IN ENCLOSURES CONTAINING INSULATING PARTS Filed July 25, 1947 3 Sheets-Sheet 2 Feb. 5, 1952 A. LATOUR DEVICE FOR PREVENTING HUMIDITY IN ENCLOSURES CONTAINING INSULATING PARTS 5 Sheets-Sheet 3 Filed July 25. 1947 INVENTOR.

Patented Feb. 5, 1952 DEVICE FOR PREVENTING HUMIDITY IN ENCLOSURES CONTAINING INSULATING PARTS Andr Latour, Grenoble, France, assignor to Etablissements Merlin & Gerin,

France Grenoble,

Application July 23, 1947, SerialNo. 763,025 In France September 10,1943

Section 1, Public Law 690, August 8, 1946 Patent expires September 10, 1963 16 Claims.

The present invention relates to dehumidifying devices for circuit breakers or the like.

It is known to dry the air in closed enclosures in order to preserve the dielectric properties of the insulating parts located in said enclosures and securing the insulation of pneumatic circuitbreakers. This drying process prevents in the insulating material the appearance of free or adsorbed water which otherwise would occur in humid air by a drop of temperature. A means frequently used to dry the enclosed air consists in a permanent weak blast of compressed air, which, by its expansion in the interior of the enclosure fills the latter with comparatively dry air, This weak blast is obtained by reduction valves, throttles or porous material, which brake the flow of the compressed air. These devices present, however, several inconveniences, because their adjustment is not stable owing to aging, or sealing by dirt, nor do they take into account the temperature conditions, which play an important part in the appearance of moisture, so that the air blast sometimes is over-abundant and sometimes insufilcient. Another inconvenience consists in the loss of compressed air.

The present invention overcomes these inconveniences by providing new means which secure an expansion of the compressed air before it enters the spaces or chambers to be dehumidified.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

Fig. 1 shows a diagram of a device according to the present invention;

Fig. 2 shows an application of the invention to an out-door high voltage circuit-breaker.

Fig. 3 shows a wiring diagram of the control of the electro-valve shown in Fig. 2; and

Fig. 4 shows another embodiment of a wiring diagram of the control of the electro-valve.

In Fig. 1 of the drawing, i is a compressor with an electric motor I, 2 a condenser, 3 a chamber with a drain orifice 4, which may be closed by a valve 5 controlled automatically by an electromagnet l6, 6 is a dryer containing a certain quantity of hygroscopic and regeneratable material 1 such, as silica gel, 8 is a heating device such as a heating resistance, 9 is a dust filter, III a pressure regulator with a closing element l0 which allows the compressed gas to flow into an auxiliary container II when a predetermined pressure is attained.

The main reservoir, such as the reservoir of an air-blast circuit-breaker is shown in 12. It is provided with a check valve is which prevents the compressed air from flowing back towards the compressor. I4 is an automatic switch controlled by a pressure responsive device, I5 is a manometric contact.

, This device operates as follows:

When the pressure in the main reservoir drops below a predetermined value, the switch i4 is closed and starts the compressor I and energizes the electro-magnet I6 which closes the drain valve 5.

As the pipes and other elements inserted between the compressor and the pressure regulator l0 have only a small internal volume, the pressure grows rapidly and attains a value preferably equal or superior to the maximal service pressure which prevails in the reservoir l2. The pressure regulator opens, permitting the filling of the auxiliary container II and of the main reservoir l2 with compressed air. It should be noted that during this operation, regardless of the initial pressure in the main reservoir II, the compressed air has passed through the drier 6 with a pressure superior to said initial pressure of the main reservoir so as to lose most of its humidity in the condenser 2 and the drier 6.

At the start of the compressor I the contact ll opens, while the contact [5 closes during the filling of the reservoir 12 and of the auxiliary container ll. When a predetermined pressure is attained in the main reservoir [2 the automatic switch ll opens, so that the compressor stops. Simultaneously, as the electro-magnet i6 is deenergized the valve 5 uncovers the .drain orifice 4 whereas the contact ll closes. The water condensed by the condenser 2 is rapidly drained oil from the chamber 3 through the orifice 4. The pressure in the elements 8-9 and particularly in the pressure regulator It decreases rapidly, so that the closing element lb of the latter at once returns to its closing position. This closing element is, however, so designed that it is not absolutely tight (this is achieved .by a very small auxiliary orifice It). This results in a slow emptying of the auxiliary container ll of compressed air, which now flows back through the dryer 6 and is exhausted atthe orifice 4.

As the contacts I! and 15 are now both closed the heating resistance 8 is supplied with current and the hygroscopic drying material I is subjected to the action of the heat and of the flow of air coming from the auxiliary container 1 I. By these combined actions, the material is completely freed from the water which it had absorbed during the compression period. When the pressure in the auxiliary container has dropped below a predetermined value, the contact l5 opens and thus switches the heating resistance 8 off. The remaining pressure, however, sufiices for securing the continuation of the backward flow of a certain quantity of air from the container 1 l which cools the hygroscopic material 1 and renders the same more effective for its action in the next compression cycle.

The heating resistance 8 is not indispensable because as soon as the valve opens the material 1 is brought back to an atmosphere of low pressure and is subjected to a flow of dry gas coming from the auxiliary container l I. These combined actions are in certain cases suflicient to secure the regeneration of the moisture absorbing material.

In certain cases, particularly when the reservoir has to operate within narrow limits of pressure, the pressure regulator I0 is not necessary and may be replaced by a check valve with imperfect tightness, which, like the pressure regulator IE], will allow the slow evacuation of the compressed air from the container i I.

It may be pointed out that the auxiliary storage space provided by the container ll may be provided only by the internal volume of the pipes located between the check valve I3 and the pressure regulator H3 (or the element which may be substituted for this regulator). In this case, the auxiliary container may be dispensed with.

The maintenance in dry conditions of the atmosphere at the interior of the enclosures of the circuit-breaker is, of course greatly facilitated by the supply for its operation of perfect dry air produced by the process described hereabove. As already mentioned this maintenance presents however still other difficulties which are overcome by the following means:

Intermittent blasts of dry compressed air are produced in the enclosures, these blasts being controlled by a valve, preferably an electro-valve controlled by a second element. This element may be an automatic contact, which closes automatically at predetermined and adjustable intervals for an adjustable duration. This contact may be also controlled by a contact-clock, a thermo-electric or a photo cell, a hygroscopic, thermometric or baroscopic device. The temporary closing of the said contact may be controlled by the change of a chosen quantity, for instance by the change of temperature.

Fig. 2 is a partial View of a pneumatic circuitbreaker in which l2 is the reservoir for compressed air, !8 is a casing housing the different parts of the breaker and serving as support for an insulator 29 Supporting an arcing chamber 2|. When the breaker is tripped the arcing chamber 21 is supplied with compressed air by a valve 22 and an insulating pipe 23.

The aim of the present invention is to prevent the formation of humidit on the inner walls of the insulator 20 and of the chamber 21, as well as on the inner and outer faces of the insulating pipe 23. In order to obtain this result, an electro valve 24, which is supplied with compressed air from the reservoir 12 injects at the proper moments a jet of compressed air into the insulator 20 and the casing 19 as well as into the pipe 23 and the chamber 21. Through a duct 25 the electro-valve 24 injects in the same manner jets of compressed air into the other poles (not shown) of the circuit-breaker as well as into all enclosures where a drying action appears necessary. The distribution of the injected air is secured by detention nozzles 21 and 28 provided with orifices calibrated according to the volume of air to be injected. If a much reduced consumption of compressed air is desired, it is necessary to render the difierent enclosures as moisture-tight as possible in order to prevent the penetration of humidity from the exterior into the enclosures, and to provide the latter with an exhaust valve as shown in 29.

Fig. 3 is a wiring diagram showing an embodiment of the control of the drying electro-valve 24 shown in Fig. 2. 30 is a relay energizing the winding 24 of the electro-valve 24 and being under the action of a retarding device 3| delaying the opening of the contact 35 of relay 30. 32 is a contact closed at suitable intervals by a clock 33 or any other timing device. 34 is the energy providing source.

This device operates as follows:

When the winding 24' of the contact 32 closes, the electro-valves 24 and the relay 30 are simultaneously energized. The electro-valve 24 opens instantaneously and supplies compressed air to the difierent nozzles such as 21, 28, until the relay 30 opens the contact 35 thereof whereby the winding 24 of the electro-valve 24 is de-energized and closes. When the contact 31 reopens after a certain time the relay 30 is reset and the whole device is ready for a new operation. When a contact clock 33 is used the closing times of the contact 32 are advantageously chosen so as to coincide with those hours of the day, during which the most accentuated drops of temperature occur. These are generally the hours corresponding to sunset or to sunrise. By an adjustment of the retarding device 3| according to the desired operating conditions, the duration of the injection time of the electro-valve 24 and consequently of the volume of injected compressed dry air may be regulated at will.

An improved arrangement for controlling the electro-valve 24 in depending the changes of the ambient temperature is shown in Fig. 4. A contact 52 controlling the winding 24 of the electrovalve 24 is actuated by a thermometric device, comprising a. container 38 and a hollow and deformable element 31 which may be designed as a manometric box or a tube in form Of an accordion.

The container 36 and the element 31 are filled with a suitable liquid and are located in a place where they are exposed to the same atmospheric conditions as the enclosures to be dried. If, for instance, the enclosures of an out-door circuitbreaker are to be dried, the temperature-responsive device is located in the vicinity of the circuitbreaker. The movable extremity of the deformable element 31 is connected to a rod 38 which is pressed against the element 31 by a compression spring 39. A sleeve 40, glides with limited friction on this rod.

The sleeve 40 consists of two halves which are held together by an annular spring 4| and pressed against the rod 38. A two-armed lever 46 pivoted about the stationary axle 43 bears at the end of the short end thereof a fork 42 between the prongs of which the sleeve 40 is located, so that every movement of the sleeve 40 is transmitted to the lever 46, so that the latter performs a rotative movement, which may be limited by a stop 48. The lever 46 bears at the end of the long arm thereof a member 5| closing the contact 52, the closing of which causes the operation of the electro-valve 24. In parallel or in series with the winding of the electro-valve 24, the winding of a relay 50 is mounted, which controls 55 and is provided with a delaying device 54. The contact 55 controls the energizing of a winding 56 of a first electro-magnet 44 acting on the lever 46 by means of a magnetic armature 53 arranged on the long arm of the lever 46 and thus causes the gliding of the sleeve along the rod 38 and the opening of the contact 52.

The operation of this device is as follows:

As soon as a temperature drop occurs, the liquid in the container 36 contracts and the rod 38 is moving upwards, under the action of the spring 39. In so doing, the rod 38 moves the sleeve 40. The contact 52 is closed and the electro-valve 24 opens and starts the operation of the time delayed relay 5!]. After a delay which can be predeterminated by the adjustment of a delaying device 54, the contact 55 closes and operates the electro-magnet 44 which, in acting against the friction of the sleeve 40, causes. the

rotation of the lever 46 and the opening of the contact 52. The electro-valve 24 recloses and the contact 55 of the delaying relay returns to its initial position. Thus the device is ready for a new operation and the cycles of the operation will be performed as long as the dropping of the temperature lasts. However, if the temperature rises, the lever 46 remains pressed against the stop 48, the rod 38 glides in the inner part of the sleeve 40 which is maintained in a fixed position, and no flow of compressed air occurs.

If it is desired to cause an operation of the electro-valve 24 independently of the thermometric device, a second electro-magnet may be added, which acts on the lever 45 in the dir rection of the closing of the contact 52. The winding 51 of the second electro-ma net 45 may be controlled by a contact 41 which is. preferably adjusted so as to act under the action of a chronometric device (not shown) or of any other device such as a barometer, a hygrometer, a psychrometer, a photo-cell or a thermo-electriccell. The contact 41 may also be controlled manually or may be electrically connected to a manually controlled contact. In this way, it is possible to control, whenever necessary, the operation of the device.

The volume of injected air is adjustable in the embodiment shown in Fig. 3 by acting on the outflow orifices of the calibrated nozzles 21, 28 and by the regulation of the duration of the opening of the eleetro-valve 24 by means of the delaying device 3|. The frequency of the injection for a given temperature drop may also be adjusted in the embodiment shown in Fig. 4 by adjusting the position of the stop 48.

What I claim is:

1. A dehumidifying device for circuit breakers or the like, comprising in combination, means for storing dry compressed air, said means forming a structural unit with the circuit breaker; an outlet connected to said storing means; an electromagnetically actuated valve arranged in said outlet and having an actuating winding; a duct connecting said outlet to a part of the circuit breaker to be dehumidified; a detention nozzle arranged at the end of said duct; an electric circuit for supplying current for said winding; a contact arranged in said circuit and adapted to be closed whenever a predetermined condition prevails; time-delayed relay means for interrupting said circuit; and means for starting the operation of said time-delayed relay means by a closure of said contact.

2. A dehumidifying device for circuit breakers or the like, comprising in combination, means for storing dry compressed air, said means forming a structural unit with the circuit breaker; an outlet connected to said storing means; an electromagnetically actuated valve arranged in said outlet and having an actuating winding; a plurality of ducts connecting said outlet, respectively, to a plurality of parts of the circuit breaker to be dehumidified; a plurality of detention nozzles arranged at the ends of said ducts, respectively; an electric circuit for supplying current for said winding; a contact arranged in said circuit and adapted to be closed whenever a predetermined condition prevails; time-delayed relay means for interrupting said circuit; and means for starting the operation of said timedelayed relay means by a closure of said contact.

3. A dehumidifying device for circuit breakers or the like, comprising in combination, means for storing dry compressed air, said means forming a structural unit with the circuit breaker; an outlet connected to said storing means; an electromagnetically actuated valve arranged in said outlet and having an actuating winding; a duct connecting said outlet to a part of the circuit breaker to be dehumidified; a detention nozzle arranged at the end of said duct; an electric circuit for supplying current for said winding; a contact arranged in said circuit and adapted to be closed and opened at predetermined times, respectively; time-delayed relay means for interrupting said circuit; and means for starting the operation of said time-delayed relay means by a closure of said contact.

4. A dehumidifying device for circuit breakers or the like, comprising in combination, means for storing dry compressed air, said means forming a structural unit with the circuit breaker; an outlet connected to said storing means; an electromagneticallyactuated valve arranged in said outlet and having an actuating winding; a duct connecting said outlet to a part of the circuit breaker to be dehumidified; a detention nozzle arranged at the end of said duct; an electric circuit for supplying current for said winding; a contact arranged in said circuit; temperature-responsive means for closing and opening said contact; time-delayed relay means for interrupting said circuit; and means for starting the operation of said time-delayed relay means by a closure of said contact.

5. A dehumidifying device for circuit breakers or the like, comprising in combination, means for storing dry compressed air, said means forming a structural unit with the circuit breaker; an outlet connected to said storing means; an electromagnetically actuated valve arranged in said outlet and having an actuating winding; a duct connecting said outlet to a part of the cir cuit breaker to be dehumidified; a detention nozzle arranged at the end of said duct; an electric circuit for supplying current for said winding; stationary contacts in said circuit; a movable contact member adapted to bridge said sta tionary contacts; a two-armed lever having a first arm connected to said movable contact member and a second arm; a temperature-responsive device connected to said second arm of said two-armed lever; time-delayed relay means for interrupting said circuit; and means for starting the operation of said time-delayed relay means on a bridging of said stationary contacts by said movable contact member.

6. A dehumidifying device for circuit breakers or the like, comprising in combination, means for storing dry compressed air, said means forming a structural unit with the circuit breaker; an outlet connected to said storing means; an electromagnetically actuated valve arranged in said outlet and having an actuating winding; a duct connecting said outlet to a part of the circuit breaker to be dehumidified; a detention nozzle arranged at the end of said duct; an electric circuit for supplying current for said winding; stationary contacts in said circuit; a movable contact member adapted to bridge said stationary contacts; a pivotally mounted element connected to said movable contact member; a temperature-responsive device connected to said pivotally mounted element; time-delayed relay means for interrupting said circuit; and means for starting the operation of said time-delayed relay means on a bridging of said stationary contacts by said movable contact member.

7. A dehumidifying device for circuit breakers or the like, comprising in combination, means for storing dry compressed air, said means forming a structural unit with the circuit breaker; an outlet connected to said storing means; an electromagnetically actuated valve arranged in said outlet and having an actuating winding; a plurality of ducts connecting said outlet, respectively, to a plurality of parts of the circuit breaker to be dehumidified; a plurality of detention nozzles arranged at the ends of said ducts, respectively; an electric circuit for supplying current for said winding; stationary contacts in said circuit; a movable contact member adapted to bridge said stationary contacts; a two-armed lever having a first arm connected to said movable contact member and a second arm; a temperature-responsive device connected to said second arm of said two-armed lever; timedelayed relay means for interrupting said circuit; and means for starting the operation of said time-delayed relay means on a bridging of said stationary contacts by said movable contact member.

8. A dehumidifying device for circuit breakers or the like, comprising in combination, means for storing dry compressed air, said means forming a structural unit with the circuit breaker; an outlet connected to said storing means; an electromagnetically actuated valve arranged in said outlet and having an actuating winding; a plurality of ducts connecting said outlet, respectively, to a plurality of parts of the circuit breaker to be dehumidified; a plurality of detention nozzles arranged at the ends of said ducts, respectively; an electric circuit for supplying current for said winding; stationary contacts in said circuit; a movable contact member adapted to bridge said stationary contacts; a pivotally mounted element connected to said movable contact member; a temperature-responsive device connected to said pivotally mounted element; time-delayed relay means for interrupting said circuit; and means for starting the operation of said time-delayed relay means on a bridging of said stationary contact by said movable contacts member.

9. A dehumidifying device for circuit breakers or the like, comprising in combination, means for storing dry compressed air, said means forming a structural unit with the circuit breaker; an outlet connected to said storing means; an electromagnetically actuated valve arranged in said outlet and having an actuating winding; a duct connecting said outlet to a part of the circuit breaker to be dehumidified; a detention nozzle arranged at the end of said duct; an electric circuit for supplying current for said winding; stationary contacts in said circuit; a movable contact member adapted to bridge said stationary contacts; a two-armed lever having a first arm connected to said movable contact member and a second arm; a temperature-responsive device connected to said second arm of said two-armed lever; a magnetic armature arranged on said first arm of said two-armed lever; an electromagnet arranged for cooperation with said armature and having a winding; a contact connected in series with said winding of said electromagnet; time-delayed relay means for closing said contact connected in series with said winding of said electromagnet; and means for starting the operation of said time-delayed relay means on a bridging of said stationary contacts by said movable contact member.

10. A dehumidifying device for circuit breakers or the like, comprising in combination, means for storing dry compressed air, said means forming a structural unit with the circuit breaker; an outlet connected to said storing means; an electromagnetically actuated valve arranged in said outlet and having an actuating winding; a duct connecting said outlet to a part of the circuit breaker to be dehumidified; a detention nozzle arranged at the end of said duct; an electric circuit for supplying current for said winding; stationary contacts in said circuit; a movable contact member adapted to bridge said stationary contacts; a two-armed lever having a first arm connected to said movable contact member and a second arm; a temperature-responsive device connected to said second arm of said twoarmed lever; a magnetic armature arranged on said first arm of said two-armed lever; a first electromagnet arranged for cooperation with said armature and having a winding; a contacts connected in series with said winding of said first electromagnet; time-delayed relay means for closing said contact connected in series with said winding of said first electromagnet; means for starting the operation of said time-delayed relay means on a bridging of said stationary contact by said movable contacts member; a second electromagnet arranged for cooperation with said armature in opposition to said first electromagnet; and switching means for energizing said second electromagnet so as to cause a bridging of said contacts by said movable contact member independently of said temperature-responsive device.

11. A dehumidifying device for circuit breakers or the like, comprising in combination, means for storing dry compressed air, said means forming a structural unit with the circuit breaker; an outlet connected to said storing means; an electromagnetically actuated valve arranged in said outlet and having an actuating winding; a duct connecting said outlet to a part of the circuit breaker to be dehumidified; a detention nozzle arranged at the end of said duct; an electric circuit for supplying current for said winding; stationary contacts in said circuit; a movable contact member adapted to bridge said stationary contacts; a twoarmed lever having a first arm connected to said movable contact member and a second arm; a

temperature-responsive device; a, rod arranged for cooperation with said temperature-responsive device so as to be controlled in the longitudinal displacement thereof by said temperature-responsive device; means for coupling said second arm of said two-armed lever with said rod whenever said rod is displaced by said temperature-responsive device beyond a predetermined limit; timedelayed relay means for interrupting said circuit; and means for starting the operation of said timedelayed relay means on a bridging of said stationary contacts by said movable contact member.

12. A dehumidifying device for circuit breakers or the like, comprising in combination, means for storing dry compressed air, said means forming a structural unit with the circuit breaker; an outlet connected to said storing means; an, electromagnetically actuated valve arranged in said outlet and having an actuating winding; a duct connecting said outlet to a part of the circuit breaker to be dehumidified; a detention nozzle arranged at the end of said duct; an electric circuit for supplying current for said winding; stationary contacts in said circuit; a movable contact member adapted to bridge said stationary contacts; a two-armed lever having a first arm connected to said movable contact member and a second arm; a stop arranged for limiting the motion of said first arm of said two-armed lever in the direction in which said movable contact member is removed from said stationary contacts; a temperature-responsive device; a rod arranged for cooperation with said temperature-responsive device; means for coupling said second arm of said two-armed lever with said rod whenever said rod is displaced by said temperature-responsive device beyond a predetermined limit; time-delayed relay means for interrupting said circuit; and means for starting the operation of said time-delayed relay means on a bridging of said stationary contacts by said movable contact member,

13. A dehumidifying device for circuit breakers or the like, comprising in combination, means for storing dry compressed air, said means forming a structural unit with the circuit breaker; an outlet connected to said storing means; an electromagnetically actuated valve arranged in said outlet and having an actuating winding; a duct connecting said outlet to a part of the circuit breaker to be dehumidified; a detention nozzle arranged at the end of said duct; an electric circuit for supplying current for said winding; stationary contacts in said circuit; a movable contact member adapted to bridge said stationary contacts; a two-armed lever having a first arm connected to said movable contact member and a second arm; a temperature-responsive device; a rod arranged for cooperation with said temperature-responsive device so as to be controlled in the longitudinal displacement thereof by said temperature-responsive device; means for coupling said second arm of said twoarmed lever with said rod whenever said rod is displaced by said temperature-responsive device beyond a predetermined limit; a magnetic armature arranged on said first arm of said twoarmed lever; an electromagnet arranged. for cooperation with said armature and having a winding; a contact connected in series with said winding of said electromagnet; time-delayed relay means for closing said contact connected in series with said winding of said electromagnet; and means for starting the operation of said time-delayed relay means by a closure of said contact.

14. A dehumidifying device for circuit breakers or the like, comprising in combination, means for storing dry compressed air, said means forming a structural unit with the circuit breaker; an outlet connected to said storing means; an electromagnetically actuated valve arranged in said outlet and having an actuating winding; a duct connecting said outlet to a part of the circuit breaker to be dehumidified; a detention nozzle arranged at the end of said duct; an electric circuit for supplying current for said winding; stationary contacts in said circuit; a movable contact member adapted to bridge said stationary contacts; a two-armed lever having a first arm connected to said movable contact member and a second arm; a temperature-responsive device; a rod arranged for cooperation with said temperature-responsive device so as to be controlled in the longitudinal displacement thereof by said temperature-responsive device; means for coupling said second arm of said two-armed lever with said rod whenever said rod is displaced by said temperature-responsive device beyond a predetermined limit; a magnetic armature arranged on said first arm of said twoarmed lever; a first electromagnet arranged for cooperation with said armature and having a winding; a contact connected in series with said winding of said first electromagnet; time-delayed relay means for closing said contact connected in series with said winding of said first electromagnet; means for starting the operation of said time-delayed relay means by a closure of said contact; a second electromagnet arranged for cooperation with said armature in opposition to said first electromagnet; and switching means for energizing said second electromagnet so as to cause a bridging of said stationary contacts by said movable contact member independently of said temperature-responsive device.

15. A dehumidifying device for circuit breakers or the like, comprising in combination, means i for storing dry compressed air, said means forming a structural unit with the circuit breaker; an outlet connected to said storing means; an electromagnetically actuated valve arranged in said outlet and having an actuating winding; a duct connecting said outlet to a part of the circuit breaker to be dehumidified; a detention nozzle arranged at the end of said duct; an electric circuit for supplying current for said winding; stationary contacts in said circuit; a movable contact member adapted to bridge said stationary contacts; a two-armed lever having a first arm connected to said movable contact member and a second arm; a stop arranged for limiting the motion of said first arm of said twoarmed lever in the direction in which said movable contact is removed from said stationary contacts; a temperature-responsive device; a rod arranged for cooperation with said temperature-responsive device so as to be controlled in the longitudinal displacement thereof by said temperature-responsive device; means for coupling said second arm of said two-armed lever with said rod whenever said rod is displaced by said temperature-responsive device beyond a predetermined limit; a magnetic armature arranged on said first arm of said two-armed lever; an electromagnet arranged for cooperation with said armature and having a winding; a contact connected in series with said winding of said electromagnet; time-delayed relay means for closing said contact connected in series with said winding of said electromagnet; and means for starting the operation of said time-delayed relay means by a closure of said contact.

16. A dehumidifying device for circuit breakers or the like, comprising in combination, means for storing dry compressed air, said means forming a structural unit with the circuit breaker; an outlet connected to said storing means; an electromagnetically actuated valve arranged in said outlet and having an actuating winding; a duct connecting said outlet to a part of the circuit breakerto be dehumidified; a detention nozzle arranged at the end of said duct; an electric circuit for supplying current for said winding; stationary contacts in said circuit; a movable contact member adapted to bridge said stationary contacts; a two-armed lever having a first arm connected to said movable contact member and a second arm; a stop arranged for limiting the motion of said first arm of said twoarmed lever in the direction in which said movable contact member is removed from said stationary contacts; a temperature-responsive device; a rod arranged for cooperation with said temperature-responsive device so as to be controlled in the longitudinal displacement thereof by said temperature-responsive device; means for coupling said second arm of said two-armed lever with said rod whenever said rod is displaced by said temperature-responsive device beyond a predetermined limit; a magnetic armature arranged on said first arm of said two-armed lever; a first electromagnet arranged for cooperation with said armature and having a winding; 9. contact connected in series with said winding of said first electromagnet; time-delayed relay means for closing said contact connected in series with said winding of said first electromagnet; means for starting the operation of said time-delayed relay means by a closure of said contact; a second electromagnet arranged for cooperation with said armature in opposition to said first electromagnet; and switching means for energizing said second electromagnet so as to cause a bridging of said contacts by said movable contact member independently of said temperature-responsive device.

ANDRE LATOUR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 275,387 Hunter Apr. 10, 1883 1,470,323 Hokanson Oct. 9, 1923 1,675,137 Sauvage June 26, 1928 1,720,896 Haderman July 16, 1929 1,937,173 Taylor Nov. 28, 1933 2,040,204 Emanueli May 12, 1936 

